... iteration sequence [16]ofaclassofquasi-contractive operators, called Zamfirescu operators, defined on a closed convex subset C of aBanachspaceX converges to the fixed point of T. The first author ... generalization of Greguˇs fixed point theorem,” Journal of Applied Sciences, vol. 6,no. 15, pp. 3160–3163, 2006.[5] C. E. Chidume, “Geometric properties of Banach spaces and nonlinear iterations,” Research Monograph, ... e,and f will be used interchangeably as p in the proof of our main theorem.As observed by Chidume [5, page 119], since the four points{x, y,Tx,Ty} of (1.2)determine six distances in X, the inequality...